An ultrafast time-resolved anisotropy study of bacteriochlorophyll a in pyridine

The transient absorption anisotropy spectrum of bacteriochlorophyll a (BChl a) in pyridine was measured in the wavelength interval 550-850 nm, 1 ps after optical excitation with a 792-nm femtosecond light pulse. In the wavelength region of Q(y) absorption and stimulated emission (775-825 nm), the anisotropy was found to be close to the theoretically expected value (0.4) for a two-level system. In the wavelength region 650-750 nm, where the transient absorption signal is dominated by excited state absorption, the anisotropy is reduced to approximately 0.18. Anisotropy kinetics were measured at several wavelengths and found to be constant within the time window 0-5 ps, showing that no internal dynamics of the BChl a molecule change the anisotropy on the time scale of tens of picoseconds.     

The Laptev Sea walrus Odobenus rosmarus laptevi: an enigma revisited

The walrus ( Odobenus rosmarus ) is in some current systematic schemes divided into three subspecies: O. r. rosmarus in the North Atlantic, O.   r. divergens in the North Pacific and O.   r. laptevi in the Laptev Sea. These three subspecies have been described as differing in body size, but the taxonomic status of O.   r. laptevi is disputed. The current study applies molecular and morphometric methods to assess the taxonomic status of O.   r. laptevi and to analyse the systematic and phylogeographic relationships between the three purported walrus subspecies. Tusk length and tusk circumference were measured from the few skulls available of O.   r. laptevi , and the obtained values were within the ranges reported for Pacific walruses. Thus, morphologically, subspecies status for O.   r. laptevi is not supported according to the Amadon–Mayr '75% rule'. Phylogenetic analyses and haplotype networks based on mitochondrial nucleotide sequence data of NADH dehydrogenase 1, 16S rRNA, cytochrome oxidase I and the d -loop of the control region of the historic O.   r. laptevi bone material and contemporary O.   r. rosmarus and O.   r. divergens showed that the Laptev Sea walrus groups with individuals from the North Pacific. Thus, the mitochondrial sequence data do not support the recognition of three walrus subspecies as reciprocally monophyletic evolutionary units with independent evolutionary histories. Only O.   r. rosmarus and O.   r. divergens meet this criterion with the present sampling. Accordingly, we recommend that Odobenus r. laptevi be abandoned and the Laptev walrus instead be recognized as the westernmost population of the Pacific walrus, Odobenus r. divergens. However, further research is recommended to assess whether the Laptev walrus could be considered as a significant unit in terms of conservation and management, since it is unique in several ecological parameters.     

Decorin in Human Colon Cancer: Localization In Vivo and Effect on Cancer Cell Behavior In Vitro

Decorin is generally recognized as a tumor suppressing molecule. Nevertheless, although decorin has been shown to be differentially expressed in malignant tissues, it has often remained unclear whether, in addition to non-malignant stromal cells, cancer cells also express it. Here, we first used two publicly available databases to analyze the current information about decorin expression and immunoreactivity in normal and malignant human colorectal tissue samples. The analyses demonstrated that decorin expression and immunoreactivity may vary in cancer cells of human colorectal tissues. Therefore, we next examined decorin expression in normal, premalignant and malignant human colorectal tissues in more detail using both in situ hybridization and immunohistochemistry for decorin. Our results invariably demonstrate that malignant cells within human colorectal cancer tissues are devoid of both decorin mRNA and immunoreactivity. Identical results were obtained for cells of neuroendocrine tumors of human colon. Using RT-qPCR, we showed that human colon cancer cell lines are also decorin negative, in accordance with the above in vivo results. Finally, we demonstrate that decorin transduction of human colon cancer cell lines causes a significant reduction in their colony forming capability. Thus, strategies to develop decorin-based adjuvant therapies for human colorectal malignancies are highly rational.     

Biomarkers of extracellular matrix metabolism (MMP-9 and TIMP-1) and risk of stroke, myocardial infarction, and cause-specific mortality: cohort study

Objective

Turnover of the extracellular matrix in all solid organs is governed mainly by a balance between the degrading matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). An altered extracellular matrix metabolism has been implicated in a variety of diseases. We investigated relations of serum levels of MMP-9 and TIMP-1 to mortality risk from an etiological perspective.

Design

The prospective Uppsala Longitudinal Study of Adult Men (ULSAM) cohort, followed from 1991–1995 for up to 18.1 years. A random population-based sample of 1,082 71-year-old men, no loss to follow-up. Endpoints were all-cause (n = 628), cardiovascular (n = 230), non-cardiovascular (n = 398) and cancer mortality (n = 178), and fatal or non-fatal myocardial infarction (n = 138) or stroke (n = 163).

Results

Serum MMP-9 and TIMP-1 levels were associated with risk of all-cause mortality (Cox proportional hazard ratio [HR] per standard deviation 1.10, 95% confidence interval [CI] 1.03–1.19; and 1.11, 1.02–1.20; respectively). TIMP-1 levels were mainly related to risks of cardiovascular mortality and stroke (HR per standard deviation 1.22, 95% CI 1.09–1.37; and 1.18, 1.04–1.35; respectively). All relations except those of TIMP-1 to stroke risk were attenuated by adjustment for cardiovascular disease risk factors. Relations in a subsample without cardiovascular disease or cancer were similar to those in the total sample.

Conclusion

In this community-based cohort of elderly men, serum MMP-9 and TIMP-1 levels were related to mortality risk. An altered extracellular matrix metabolism may be involved in several detrimental pathways, and circulating MMP-9 or TIMP-1 levels may be relevant markers thereof.     

Genetic population structure, queen supersedure and social polymorphism in a social Hymenoptera

In social insects, the emergence of multiple queening is linked to changes in a suite of traits such as the reproductive life span of queens, mating patterns and population structure. We investigated queen turnover, colony longevity, spatial distribution patterns and genetic differentiation in a population of the socially polymorphic ant Formica fusca. Genetic differentiation between the social forms was absent, and mating patterns were similar in the two forms. The spatial distribution of single- and multi-queen colonies indicated an absence of colony reproduction by budding in both colony types. However, the rate of queen supersedure was high in multi-queen colonies and absent in single-queen ones. The social structure of colonies remained stable across years, but colony mortality did not differ between the two social forms. These results imply that differences between social types may appear and persist also in sympatry, and that these differences may occur in some traits, but not others, despite the presence of homogenizing gene flow.     

Long-distance dispersal of a wolf, <Emphasis Type="Italic">Canis lupus</Emphasis>, in northwestern Europe

Several mammal species have recolonized their historical ranges across Europe during the last decades. In November 2012, a wolf-looking canid was found dead in Thy National Park (56° 56′ N, 8° 25′ E) in Jutland, Denmark. DNA from this individual and nine German wolves were genotyped using a genome-wide panel of 22,163 canine single nucleotide polymorphism (SNP) markers and compared to existing profiles based on the same marker panel obtained from northeastern Polish (n?=?13) wolves, domestic dogs (n?=?13) and known wolf-dog hybrids (n?=?4). The Thy canid was confirmed to be a wolf from the German-western Polish population, approximately 800 km to the southeast. Access to the German reference database on DNA profiles based on 13 autosomal microsatellites of German wolves made it possible to pinpoint the exact pack origin of the Thy wolf in Saxony, Germany. This was the first documented observation of a wolf in Denmark in 200 years and another example of long-distance dispersal of a carnivore.     

A secretory system for bacterial production of high-profile protein targets

Escherichia coli represents a robust, inexpensive expression host for the production of recombinant proteins. However, one major limitation is that certain protein classes do not express well in a biologically relevant form using standard expression approaches in the cytoplasm of E. coli. To improve the usefulness of the E. coli expression platform we have investigated combinations of promoters and selected N-terminal fusion tags for the extracellular expression of human target proteins. A comparative study was conducted on 24 target proteins fused to outer membrane protein A (OmpA), outer membrane protein F (OmpF) and osmotically inducible protein Y (OsmY). Based on the results of this initial study, we carried out an extended expression screen employing the OsmY fusion and multiple constructs of a more diverse set of human proteins. Using this high-throughput compatible system, we clearly demonstrate that secreted biomedically relevant human proteins can be efficiently retrieved and purified from the growth medium.